Alkynes Flashcards
Alkynes are made up what type of bonds
Carbon-carbon triple bond
The triple bond consists of
2 pi bonds
1sigma bond
Each carbon is what hybridised with what kind of geometry and bind angle of
Sp hybridised
Linear geometry
Bind angle of 180°
Alkyne is how many hydrogen less than alkane and how many hydrogen less than alkene
4 hydrogen less than alkane.
2 hydrogen less than alkene.
The Lindlar’s catalyst is made up of..
5% of Palladium calcium carbonate(Caco³)
Lead Acetate ( Pb(CH³COO)²
Quinoline
What are the methods of preparation for Alkynes
- Dehydrohalogenation of 1,2- dihalides
- Elimination of Halogens from 1,1,2,2- tetrahalides
- Alkylation of terminal Acetylenes with Alkyl halides.
In the Elimination of Halogens from 1,1,2,2- tetrahalides what catalyst is used
Zn in the presence of Alcohol
In the alkylation of terminal alkynes with Alkyl halides is carried out in the presence of
A strong base like Sodium Amide(NaNH³).
This is one of the common methods for the synthesis of longer carbon-carbon chain alkynes.
Physical properties of alkynes
- Alkynes have low melting and low boiling points
- Alkynes are soluble in organic solvents and insoluble in water
- Melting point and boiling point increases as the number of carbon increases
What catalyst reacts with alkynes to give alkanes
Palladium, platinum OR Nickel catalyst
What catalyst reacts with alkyne to give Cis-alkene
Lindlar’s Catalyst
Alkynes reacts with Na/NH³ to give..
Trans-Alkene
Why do alkynes undergo addition reaction?
They undergo addition reaction because they contain relatively weak pi-bonds.
Alkynes polymerize to give …
Benzene or substituted benzene when the conditions are appropriate.
What is Tautomerization?
Tautomerization isa net process by which protons are transferred from one site to another by a series of steps in which the solvent is an intermediary. From: Organic Chemistry
